Generally, conventional exercise equipment may utilize a force against which to apply pressure to exercise muscle tissue and promote muscle development. Examples of such conventional exercise equipment range from cumbersome cast iron dumbbells to elaborate and expensive exercise machines such as those found in health clubs. Existing exercise equipment, however, may differ in the arrangement which produces the force against which pressure is applied. For example, conventional cast iron dumbbells utilize the force of gravity and the mass of a cast iron weight against which pressure is applied, usually in lifting the dumbbell. Other exercise machines employ a pulley system to lift weights or the tension of a spring or elastic band against which to apply pressure. Although these existing exercise machines may be satisfactory, they are often bulky, expensive and difficult to operate. For example, exercise machines, such as those commonly found in most health clubs, are often larger than the operator and require extensive instructional guidance before the user may fully gain the benefit of operation.
The design of existing exercise equipment has tended toward state of the art in man's struggle to improve muscle tone and achieve fitness. State of the art, however, does not necessarily mean bigger and more expensive. Advances have been made in exercise equipment design which allow many to exercise muscle tissue without resorting to the bulky and expensive existing machines. For example, Boatcallie U.S. Pat. No. 4,861,022 describes a muscle exerciser employing elastic bands particularly adapted to exercising chest muscles through the use of forearm force. Boatcallie, however, may be difficult to adapt to other muscle groups due to its design limitations aimed at forearm usage. U.S. Design Pat. No. Des. 322,827 discloses an exerciser which employs a coil to provide resistance against which the operator applies pressure. An exerciser commercially available under the trademark "THIGHTHINNER" employs a similar coil. Both exercisers operate on a principle similar to commercially available hand strengtheners where the operator's hand grasps two extensions of a coil and squeezes them toward one another. The exerciser is essentially a larger version of the hand strengthener utilized to exercise various muscle groups. The coil, however, may be subject to damage through improper use, such as forcing the extensions away from one another, either intentionally or by accident, rather than toward one another as in normal use. Such improper use may distort the positioning of the extensions, as well as, effect the resistance provided by the coil. Similar disadvantages may result by twisting of the coil itself during normal use.
The above examples illustrate the lack of an exercise device which can be conveniently used to exercise a variety of muscle groups and which is also designed to reduce damage to the exercise device by overuse, overextension or twisting. A need therefore exists for an exercise device which reduces the drawbacks associated with existing exercise devices and which provides advantages not found in such exercise devices.